1. Field of Invention
The present invention relates to a lighting device, more particularly relates to a lighting device having a direct-current driven lighting module.
2. Description of Related Art
The fluorescent lighting lamp in the present market usually has a ballast, and there are two styles of the ballast: an inductive ballast and an electronic ballast. A LED in a LED lighting bar needs to be driven by DC (direct current), thus a power supply module which can convert AC (alternating current) into DC shall be disposed in the LED lighting lamp for being connected to an AC power source. As a result, the LED lighting bar can be disposed in the fluorescent lighting lamp.
However, the inductive ballast and the electronic ballast are corresponding to the different power supply modules, the inductive ballast is only corresponding to a switch-mode power supply module, the electronic ballast is only corresponding to a specific power supply module, and no general power supply module in the present market is corresponding for the inductive ballast and the electronic ballast. Therefore, the manufacturing firm needs to prepare two kinds of the lighting lamp in stock to response the demand of clients. Furthermore, when the clients need to replace the lighting lamp and cannot identify the kinds of the ballast or the power supply module, the lighting lamp will be mounted incorrectly and cannot be turned on.
Furthermore, a direct-current driven lighting module in the lighting lamp, for example a light-emitting diode lighting module (also known as light bar), is composed of a plurality of the light-emitting diodes disposed on a circuit board, and the light-emitting diodes are coupled or electrical connected to each other in series and/or parallel via a printed wire on the circuit board. The light bar is used in the backlit of a LCD Monitor or used in a lamp. However, after the light-emitting diodes is mounted on the light bar, the connecting way of the light-emitting diodes is fixed or not adjusted, so the voltage-current characteristic of the light bar cannot be changed, and it is not flexible.
Therefore, a lighting device which is corresponding for the inductive ballast and the electronic ballast and a lighting module whose voltage-current characteristic is adjustable are desirous for a person skilled in the art.